Anisotropy of Effective Electron Mass in Gallium Phosphide

Abstract

Approximate solutions of the effective mass Schrödinger equation for donor states in gallium phosphide are calculated by a variational method with a parameter γ=m_⊥⁄m_⁄⁄. Comparison of the calculated energies of p-like states of donor with the experimental energy separations between several excited states from the “two-electron” recombination radiation of excitons bound to neutral donors by Dean et al., determines the transverse mass m_⊥=(0.21±0.01)m₀ and the longitudinal mass m_⁄⁄=(1.15±0.05)m₀ at the bottom of the conduction band in gallium phosphide.